As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option for processing and storing information is an information handling system. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, educational, governmental, or other purposes thereby allowing users to take advantage of the value of the information.
Because technology and information handling needs and requirements vary between different users and/or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
One type of information handling system is commonly referred to as a server or server system. As suggested by its name, a server system might be described as an information handling system that provides a service to one or more other information handling systems. Server systems include, as examples, application servers dedicated to running specified software applications, database servers that provide database services, file servers that provide file services, web servers that communicate with HTTP (Hypertext transfer protocol) clients to receive and respond to HTTP requests, and numerous other types of servers.
Another type of information handling system is commonly referred to as a personal computer, such as a laptop or desktop computer. FIG. 1 shows one example of a prior art information handling system 1 that may be referred to as a desktop computer. Information handling system 1 includes a host 10, a monitor 20, a keyboard 30, and a mouse 32. Information handling system 1 may include any components, devices, and/or peripherals configured to facilitate or support the operation of information handling system 1.
Host 10 may be a server, a laptop, and/or any other type of information handling system. Host 10 includes processing resources, e.g., one or more central processing units (CPUs) and storage resources that are accessible to the processing resources. Storage resources may include volatile storage or memory and/or persistent storage, e.g., disk storage, flash memory or other type of erasable read only memory (ROM), and the like. Host 10 may also include various other peripheral or I/O devices known in the field of data processing system design.
CPUs and/or other electronic components generate heat as a byproduct of operation. Electronics designers and users may find that using one or more cooling systems associated with an electronics component increases operating speeds and/or efficiency of the components so cooled. Some benefits of increased operating speeds may include, for example, an increase in how quickly and/or efficiently information may be processed, stored, and/or communicated.
FIG. 2 depicts a prior art cooling system 2 configured for use with a CPU or processor 40. Cooling system 2 includes a heat sink 50, a fan 60, and a controller 70. Cooling system 2 as shown is a common design used to facilitate heat transfer away from processor 40.
In the example shown, heat sink 50 includes a mass with a large heat capacity in comparison to that of processor 40. The large heat capacity facilitates rapid heat transfer from processor 40 into heat sink 50. Heat sink 50 also includes one or more fins 52. Fins 52 create a large surface area which increases the heat transfer from heat sink 50 to the surrounding air.
In addition, fan 60 is configured to increase the flow of air across heat sink 50 and fins 52. Increased flow of air, or some other coolant, results in increased heat convection away from heat sink 50 and fins 52. Persons having ordinary skill in the art will recognize that heat sink performance may be improved with a variety of methods, such as increasing the thermal conductivity of heat sink 50, increasing the surface area of heat sink 50 and/or fins 52, and/or by increasing the flow rate of the coolant across heat sink 50 and fins 52.
Controller 70 is a component or device configured to control the operation of fan 60 based on the actual temperature of processor 40. In the example shown, controller 70 receives a signal correlating to the temperature of processor 40 as measured by a temperature probe 42. Temperature probe 42 may be a thermocouple or another sensor configured to measure the temperature of processor 40 and communicate the measurement to controller 70.
Fan 60 includes a motor 62 configured to rotate fan 60. Controller 70 is configured to provide power to motor 62 (e.g., by controlling a power supply coupled to motor 62). Controller 70 may also be configured to control the speed of rotation of fan 60. In this example, controller 70 may increase the speed of fan 60 in response to an increased temperature measurement provided by temperature probe 42. Increasing the speed of fan 60 increases the flow rate of air forced across heat sink 50 and fins 52. In this manner, controller 70 is configured to increase the heat transfer away from processor 40 if the temperature of processor 40 increases.
Typically, processor temperatures are controlled with respect to a specified thermal profile promulgated by the designer of the processor. A thermal profile defines the operating thermal limits of a processor. The purpose of a thermal profile is to ensure optimal operating conditions as well as the long-term reliability of a processor. For example, INTEL propounds up to two different thermal specifications for its processors, including one profile identified as minimizing the chances of processor throttling and one allowing an increased chance of processor throttling in exchange for decreased cooling requirements. Both specifications meet the requirements to support Intel reliability requirements. Typical information handling systems are configured during fabrication to operate their processors within temperatures defined by these or similar thermal profiles.
“Processor throttling” refers to a phenomenon sometimes observed when processors operate at increased temperature. Specifically, transistor performance may be slowed at certain raised temperatures because the speed of switch operation is reduced. In addition, prolonged exposure to increased temperature may result in an increased failure rate. Many information handling systems include governors configured to measure throttling effects based on feedback from the processors. The thermal profiles discussed above may include an upper temperature limit calculated to reduce and/or eliminate the chance that a processor will suffer processor throttling.
FIG. 3 is a graphical representation of two thermal profiles related to processors such as processor 40 described in relation to FIG. 2. FIG. 3 is a graph of the temperature at the center of a processor (TCASE) versus the power dissipation requirement (Power). The power dissipation requirement defines the amount of power that must be removed from a processor to operate within a given thermal profile. Along the y-axis (TCASE), FIG. 3 depicts a dotted line labeled TControl. As long as ICASE remains at or below TControl, the required power dissipation from the processor is not specified with respect to a thermal profile. When ICASE exceeds TControl, processor 40 is operating within a thermal profile regime.
Line A represents a high-reliability temperature profile (Profile A) in which the required power dissipation increases rapidly as ICASE increases. Line B represents a more aggressive thermal profile (Profile B), in which ICASE is allowed to increase more dramatically than the profile represented by Line A. As shown on the y-axis (TCASE), the maximum temperature allowed under Profile A is lower than the maximum temperature allowed under Profile B. Under either profile, the thermal design power (TDP) is a target maximum power dissipation value or requirement for processor 40. Current information handling systems are designed to control any cooling systems, and therefore processor temperature, based on a thermal profile selected at the time the information handling system is fabricated.
In exchange for reliability and/or high performance, operation of a cooling system presents its own costs in power consumption, noise, manufacturing complexity, failure modes and/or additional negative consequences. Designers, manufacturers, purchasers and users of information handling systems, CPUs, integrated circuits, microprocessors, and/or any other electronics components may be well served by techniques and apparatus that provide increased performance without the typically attendant negative consequences. Under the current regime, restricting the processor temperature to TCASE,Max instead of a true temperature maximum may reduce the power consumption and cost resulting from a cooling system, but sacrifices some potential performance increase.
Power consumption has become an increasingly important aspect or feature of a server system and other information handling system platforms. In any information handling system, cooling systems consume power. It is anticipated that this power consumption will increase as the speed and efficiency of electronics components increases. While the purchase price and installation cost of a system including a cooling system may be a one time financial impact, the total cost of ownership may be greatly affected by the ongoing cost of energy consumed by the system. Any system or method for reducing the power consumption of cooling systems may offer an improvement in the overall performance of information handling systems.